Adjustable head rest



FIG. 1 is a side and front perspective view of an adjustable head rest showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a left side view thereof; and,

FIG. 8 is a side and rear perspective view thereof. 

CLAIM I claim the ornamental design for an adjustable head rest, as shown and described. 